For current various protection techniques, protection and recovery for services in a single domain are mainstream; but for protection and recovery of a cross-domain service, since protection protocols between various domains can not interact, a failure easily occur in the interconnecting node between two domains, so that the cross-domain service can not be recovered and protected timely.
Currently, the problem that protection methods for services in a single domain can not protect and recover a cross-domain service is solved mainly from the following aspects: 1. setting up or configuring a cross-domain end-to-end protection path to recover and protect a service, as shown in FIG. 1 (FIG. 1 is a diagram of cross-domain end-to-end protection according to related techniques); 2. using an in-domain protection method to protect and recover the cross-domain service segment by segment in a path to ensure independence of recovery and protection in each domain, so as to realize interaction of the cross-domain protection, see FIG. 2 (FIG. 2 is a diagram of cross-domain segment-by-segment protection according to related techniques). For the first method, since configuring a cross-domain protection path requires conformance of operation, administration, maintenance (simply OAM for short) protocols (such as an corresponding automatic protection switching (APS) message or a corresponding protection switching coordination (PSC) message and so on), it is difficult to realize; for the second method, since protection is independent in each domain, its interconnecting backup node does not know a protection path corresponding to a working path in another domain, so that switching to the protection path in another domain can not be triggered.
For the second method, it realizes the function of cross-domain protection interaction mainly by extending messages of OAM protocols (such as APS or PSC and so on). However, because an OAM detection mechanism based on a link layer is adopted during the ring network protection, when a failure occurs, APS messages or PSC messages sent along the link layer on the ring network are not aimed at APS messages or PSC messages on a specific path, and this is not convenient to carry the path to a corresponding working path on another adjacent domain, thereby causing cross-domain protection between two adjacent domains difficult to realize.
Aiming at the problem of difficult realization of cross-domain protection in the related techniques, effective solutions are not presented so far.